What is a good hyd. flat tappet cam for a 350 with vortec heads? These are assembled from the factory vortec heads. The motor will probably be carbureted too.

 

Can't go over .460-.470" lift.

 

comp xe262

 

I wouldnt use the factory springs on ANY aftermarket camshaft.

 

Yeah, I'd go with the CompCams XE262. It's 218/224 @.050 duration, lift of .462/.469. I've been running that for awhile on the stock valve springs with zero problems (although I want to replace them to be on the safe side shortly). The XE268 is a popular choice but is even more iffy on the springs and doesn't yield but around 8-10hp over the 262 on this setup, not worth the potential problems with the stock springs, but if you decide to swap the valve springs while the heads are off (a very good idea) I'd go with that one....

 

I third the XE262 cam, if the rest of the enine is setup right you could make 350hp with this cam and vortec heads. Good Luck.

 

Thanks for all your suggestions. If I choose to swap valve springs, what would be a good set that fits right in?

 

I had a 268H one time with stock heads and loved it. It had .460 lift on both sides. Duration was 218 @ .050. It was very powerful and had a good idle. When I ended up getting vortec heads I went with the XE 268 K-kit. It came with the XE 268 cam, lifters, timing chain, springs, retainers, and valve seals. The machine shop put the springs on the heads to match the cam. Also, I was able to put 1.6 roller rockers on with no trouble after that. My opinion is that the money for the springs and the machine work was well worth the money. If you can't afford the springs and machine work then get the 268H High Energy cam. It works well with a stock converter and a high gear also.

 

The Edelbrock Performer RPM valve springs p/n #5703 looked like they would swap right in... ( same diameter and installed height) am I right? Or do the springs seats need to be machined?

 

Do yourself a big favor and get springs that the cam manufactuer recommends. If you get the 262h, those would probably be the 981's. They're $55ish. They fit too.

Spring seats only need work if you plan on going larger than the 1.26" OD.

 

What will need machined is the Stud's for replacing screw in.. That I say is a must change with a Vortec head..

 

What is the general rule of thumb in valve lift for when its a good idea to switch to screw in rocker studs?

 

So so true.................

It is always an excellent idea to buy the matching springs.

Less headaches to deal with in the long run, you wont regret the extra upfront work thousands of miles down the road.

 

My friends running Comp's 981 springs in his vortecs. The problem is that vortecs have large valve guide bosses - They hit the dampner inside the spring. He talked to someone at Comp Cams and they actually told him it'd be alright to remove the dampners (I didnt think that was a good idea - but its worked for awhile now). He also shaved the bottom of his retainers slightly to gain enough clearance to run his cam. Once again, not something I'd really recommend BUT it works!

Back to the point ...if you are going to be running those springs with vortecs dont expect them to drop in. Take your heads to a machine shop and have them cut down the guides and whatnot... Actually if you're gonna do all that other machine work you might as well buy 1.46" springs and have the heads machined for them then you never have to take these puppies off down the road when you get the urge to throw in a more silly cam.